python - feedparser、エントリの値がありません

Question

NOAA から次の RSS フィードを解析しようとしています: http://www.nhc.noaa.gov/rss_examples/gis-ep-20130530.xml

このセクションを除いて、うまく機能します：

    <item>
    <title>Summary - Remnants of BARBARA (EP2/EP022013)</title>
    <guid isPermaLink="false">summary-ep022013-201305302032</guid>
    <pubDate>Thu, 30 May 2013 20:32:00 GMT</pubDate>
    <author>nhcwebmaster@noaa.gov (NHC Webmaster)</author>
    <link>
    http://www.nhc.noaa.gov/text/refresh/MIATCPEP2+shtml/302031.shtml
    </link>
    <description>
    ...BARBARA DISSIPATES... ...THIS IS THE LAST ADVISORY... As of 2:00 PM PDT Thu May         30 the center of BARBARA was located at 18.5, -94.5 with movement NNW at 3 mph. The minimum         central pressure was 1005 mb with maximum sustained winds of about 25 mph.
    </description>
    <gml:Point>
    <gml:pos>18.5 -94.5</gml:pos>
    </gml:Point>
    **<nhc:Cyclone>
            <nhc:center>18.5, -94.5</nhc:center>
            <nhc:type>REMNANTS OF</nhc:type>
            <nhc:name>BARBARA</nhc:name>
            <nhc:wallet>EP2</nhc:wallet>
            <nhc:atcf>EP022013</nhc:atcf>
            <nhc:datetime>2:00 PM PDT Thu May 30</nhc:datetime>
            <nhc:movement>NNW at 3 mph</nhc:movement>
            <nhc:pressure>1005 mb</nhc:pressure>
            <nhc:wind>25 mph</nhc:wind>
            <nhc:headline>
            ...BARBARA DISSIPATES... ...THIS IS THE LAST ADVISORY...
            </nhc:headline>
    </nhc:Cyclone>**
    </item>

BOLD のセクションは、feedparser によって解析されていません。カスタムタグが解析に含まれていることを確認する方法はありますか?

検証：

>>> import feedparser
>>> f = feedparser.parse('http://www.nhc.noaa.gov/rss_examples/gis-ep-20130530.xml')
>>> f.entries[1]['description']
u'Shapefile last updated Thu, 30 May 2013 15:03:01 GMT'
>>> f.entries[1]['nhc_cyclone']
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "feedparser.py", line 375, in __getitem__
    return dict.__getitem__(self, key)
KeyError: 'nhc_cyclone'

の出力>>> f: https://gist.github.com/mustafa0x/6199452